Baseline Correction

Removes continuum/baseline drift from LIBS spectra. Supported methods: "snip" (Statistics-sensitive Non-linear Iterative Peak-clipping, Morhac/Ryan), "als" (Asymmetric Least Squares smoothing, Eilers & Boelens), "rolling_ball" (morphological), "linear" (two-endpoint interpolation), or "polynomial" (low-order polynomial fit of baseline-only regions).

Usage

ls_baseline(
  x,
  method = "snip",
  iterations = 100,
  order = 3,
  lambda = 1e+05,
  p = 0.01,
  radius = 50,
  ...
)

Arguments

x

A ls_spectrum() or ls_dataset() object.

method

Character. One of "snip", "als", "rolling_ball", "linear", "polynomial". Default "snip".

iterations

Integer. Iterations for iterative methods (SNIP, ALS). Default 100.

order

Integer. Polynomial order for "polynomial". Default 3.

lambda

Numeric. Smoothness parameter for ALS. Default 1e5.

p

Numeric. Asymmetry parameter for ALS (0 < p < 1). Default 0.01.

radius

Integer. Rolling-ball radius in channels. Default 50.

...

Reserved for future use.

Value

Same class as input with baseline-corrected intensities; the estimated baseline is stored in the baseline element for inspection.

Examples

spec <- ls_simulate_spectrum(seed = 1)
corr <- ls_baseline(spec, method = "snip")
is.null(corr$baseline)
#> [1] FALSE